/*
 *  ircd-hybrid: an advanced Internet Relay Chat Daemon(ircd).
 *  snprintf.c: Functions for printing to a length-limited string.
 *
 *  Copyright (C) 2002 by the past and present ircd coders, and others.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 *  $Id: snprintf.c 147 2005-12-26 02:52:10Z jon $
 */

/**************************************************************
 * Original header, taken from mutt...:
 * Patrick Powell Tue Apr 11 09:48:21 PDT 1995
 * A bombproof version of doprnt (dopr) included.
 * Sigh.  This sort of thing is always nasty do deal with.  Note that
 * the version here does not include floating point...
 *
 * snprintf() is used instead of sprintf() as it does limit checks
 * for string length.  This covers a nasty loophole.
 *
 * The other functions are there to prevent NULL pointers from
 * causing nast effects.
 *
 * More Recently:
 *  Brandon Long <blong@fiction.net> 9/15/96 for mutt 0.43
 *  This was ugly.  It is still ugly.  I opted out of floating point
 *  numbers, but the formatter understands just about everything
 *  from the normal C string format, at least as far as I can tell from
 *  the Solaris 2.5 printf(3S) man page.
 *
 *  Brandon Long <blong@fiction.net> 10/22/97 for mutt 0.87.1
 *    Ok, added some minimal floating point support, which means this
 *    probably requires libm on most operating systems.  Don't yet
 *    support the exponent (e,E) and sigfig (g,G).  Also, fmtint()
 *    was pretty badly broken, it just wasn't being exercised in ways
 *    which showed it, so that's been fixed.  Also, formated the code
 *    to mutt conventions, and removed dead code left over from the
 *    original.  Also, there is now a builtin-test, just compile with:
 *           gcc -DTEST_SNPRINTF -o snprintf snprintf.c -lm
 *    and run snprintf for results.
 * 
 *  Thomas Roessler <roessler@guug.de> 01/27/98 for mutt 0.89i
 *    The PGP code was using unsigned hexadecimal formats. 
 *    Unfortunately, unsigned formats simply didn't work.
 *
 *  Michael Elkins <me@cs.hmc.edu> 03/05/98 for mutt 0.90.8
 *    The original code assumed that both snprintf() and vsnprintf() were
 *    missing.  Some systems only have snprintf() but not vsnprintf(), so
 *    the code is now broken down under HAVE_SNPRINTF and HAVE_VSNPRINTF.
 *
 **************************************************************/

#include "stdinc.h"
#if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)


#include "irc_string.h"

/* varargs declarations: */

# include <stdarg.h>
# define HAVE_STDARGS		/* let's hope that works everywhere (mj) */
# define VA_LOCAL_DECL   va_list ap
# define VA_START(f)     va_start(ap, f)
# define VA_SHIFT(v,t)  ;	/* no-op for ANSI */
# define VA_END          va_end(ap)

/*int snprintf (char *str, size_t count, const char *fmt, ...);*/
/*int vsnprintf (char *str, size_t count, const char *fmt, va_list arg);*/

static void dopr(char *buffer, size_t maxlen, const char *format, va_list args);
static void fmtstr(char *buffer, size_t * currlen, size_t maxlen,
		   char *value, int flags, int min, int max);
static void fmtint(char *buffer, size_t * currlen, size_t maxlen,
		   long value, int base, int min, int max, int flags);
static void fmtfp(char *buffer, size_t * currlen, size_t maxlen,
		  long double fvalue, int min, int max, int flags);
static void dopr_outch(char *buffer, size_t * currlen, size_t maxlen, char c);

/*
 * dopr(): poor man's version of doprintf
 */

/* format read states */
#define DP_S_DEFAULT 0
#define DP_S_FLAGS   1
#define DP_S_MIN     2
#define DP_S_DOT     3
#define DP_S_MAX     4
#define DP_S_MOD     5
#define DP_S_CONV    6
#define DP_S_DONE    7

/* format flags - Bits */
#define DP_F_MINUS 	(1 << 0)
#define DP_F_PLUS  	(1 << 1)
#define DP_F_SPACE 	(1 << 2)
#define DP_F_NUM   	(1 << 3)
#define DP_F_ZERO  	(1 << 4)
#define DP_F_UP    	(1 << 5)
#define DP_F_UNSIGNED 	(1 << 6)

/* Conversion Flags */
#define DP_C_SHORT   1
#define DP_C_LONG    2
#define DP_C_LDOUBLE 3

#define char_to_int(p) (p - '0')
#undef MAX
#define MAX(p,q) ((p >= q) ? p : q)

static void
dopr(char *buffer, size_t maxlen, const char *format, va_list args)
{
	char ch;
	long value;
	long double fvalue;
	char *strvalue;
	int min;
	int max;
	int state;
	int flags;
	int cflags;
	size_t currlen;

	state = DP_S_DEFAULT;
	currlen = flags = cflags = min = 0;
	max = -1;
	ch = *format++;

	while(state != DP_S_DONE)
	{
		if((ch == '\0') || (currlen >= maxlen))
			state = DP_S_DONE;

		switch (state)
		{
		case DP_S_DEFAULT:
			if(ch == '%')
				state = DP_S_FLAGS;
			else
				dopr_outch(buffer, &currlen, maxlen, ch);
			ch = *format++;
			break;
		case DP_S_FLAGS:
			switch (ch)
			{
			case '-':
				flags |= DP_F_MINUS;
				ch = *format++;
				break;
			case '+':
				flags |= DP_F_PLUS;
				ch = *format++;
				break;
			case ' ':
				flags |= DP_F_SPACE;
				ch = *format++;
				break;
			case '#':
				flags |= DP_F_NUM;
				ch = *format++;
				break;
			case '0':
				flags |= DP_F_ZERO;
				ch = *format++;
				break;
			default:
				state = DP_S_MIN;
				break;
			}
			break;
		case DP_S_MIN:
			if(isdigit((unsigned char) ch))
			{
				min = 10 * min + char_to_int(ch);
				ch = *format++;
			}
			else if(ch == '*')
			{
				min = va_arg(args, int);
				ch = *format++;
				state = DP_S_DOT;
			}
			else
				state = DP_S_DOT;
			break;
		case DP_S_DOT:
			if(ch == '.')
			{
				state = DP_S_MAX;
				ch = *format++;
			}
			else
				state = DP_S_MOD;
			break;
		case DP_S_MAX:
			if(isdigit((unsigned char) ch))
			{
				if(max < 0)
					max = 0;
				max = 10 * max + char_to_int(ch);
				ch = *format++;
			}
			else if(ch == '*')
			{
				max = va_arg(args, int);
				ch = *format++;
				state = DP_S_MOD;
			}
			else
				state = DP_S_MOD;
			break;
		case DP_S_MOD:
			/* Currently, we don't support Long Long, bummer */
			switch (ch)
			{
			case 'h':
				cflags = DP_C_SHORT;
				ch = *format++;
				break;
			case 'l':
				cflags = DP_C_LONG;
				ch = *format++;
				break;
			case 'L':
				cflags = DP_C_LDOUBLE;
				ch = *format++;
				break;
			default:
				break;
			}
			state = DP_S_CONV;
			break;
		case DP_S_CONV:
			switch (ch)
			{
			case 'd':
			case 'i':
				if(cflags == DP_C_SHORT)
					value = va_arg(args, short int);
				else if(cflags == DP_C_LONG)
					value = va_arg(args, long int);
				else
					value = va_arg(args, int);
				fmtint(buffer, &currlen, maxlen, value, 10, min, max, flags);
				break;
			case 'o':
				flags |= DP_F_UNSIGNED;
				if(cflags == DP_C_SHORT)
					value = va_arg(args, unsigned short int);
				else if(cflags == DP_C_LONG)
					value = va_arg(args, unsigned long int);
				else
					value = va_arg(args, unsigned int);
				fmtint(buffer, &currlen, maxlen, value, 8, min, max, flags);
				break;
			case 'u':
				flags |= DP_F_UNSIGNED;
				if(cflags == DP_C_SHORT)
					value = va_arg(args, unsigned short int);
				else if(cflags == DP_C_LONG)
					value = va_arg(args, unsigned long int);
				else
					value = va_arg(args, unsigned int);
				fmtint(buffer, &currlen, maxlen, value, 10, min, max, flags);
				break;
			case 'X':
				flags |= DP_F_UP;
			case 'x':
				flags |= DP_F_UNSIGNED;
				if(cflags == DP_C_SHORT)
					value = va_arg(args, unsigned short int);
				else if(cflags == DP_C_LONG)
					value = va_arg(args, unsigned long int);
				else
					value = va_arg(args, unsigned int);
				fmtint(buffer, &currlen, maxlen, value, 16, min, max, flags);
				break;
			case 'f':
				if(cflags == DP_C_LDOUBLE)
					fvalue = va_arg(args, long double);
				else
					fvalue = va_arg(args, double);
				/* um, floating point? */
				fmtfp(buffer, &currlen, maxlen, fvalue, min, max, flags);
				break;
			case 'E':
				flags |= DP_F_UP;
			case 'e':
				if(cflags == DP_C_LDOUBLE)
					fvalue = va_arg(args, long double);
				else
					fvalue = va_arg(args, double);
				break;
			case 'G':
				flags |= DP_F_UP;
			case 'g':
				if(cflags == DP_C_LDOUBLE)
					fvalue = va_arg(args, long double);
				else
					fvalue = va_arg(args, double);
				break;
			case 'c':
				dopr_outch(buffer, &currlen, maxlen, va_arg(args, int));
				break;
			case 's':
				strvalue = va_arg(args, char *);
				if(max < 0)
					max = maxlen;	/* ie, no max */
				fmtstr(buffer, &currlen, maxlen, strvalue, flags, min, max);
				break;
			case 'p':
				strvalue = va_arg(args, void *);
				fmtint(buffer, &currlen, maxlen, (long) strvalue, 16, min, max,
				       flags);
				break;
			case 'n':
				if(cflags == DP_C_SHORT)
				{
					short int *num;
					num = va_arg(args, short int *);
					*num = currlen;
				}
				else if(cflags == DP_C_LONG)
				{
					long int *num;
					num = va_arg(args, long int *);
					*num = currlen;
				}
				else
				{
					int *num;
					num = va_arg(args, int *);
					*num = currlen;
				}
				break;
			case '%':
				dopr_outch(buffer, &currlen, maxlen, ch);
				break;
			case 'w':
				/* not supported yet, treat as next char */
				ch = *format++;
				break;
			default:
				/* Unknown, skip */
				break;
			}
			ch = *format++;
			state = DP_S_DEFAULT;
			flags = cflags = min = 0;
			max = -1;
			break;
		case DP_S_DONE:
			break;
		default:
			/* hmm? */
			break;	/* some picky compilers need this */
		}
	}
	if(currlen < maxlen - 1)
		buffer[currlen] = '\0';
	else
		buffer[maxlen - 1] = '\0';
}

static void
fmtstr(char *buffer, size_t * currlen, size_t maxlen, char *value, int flags, int min, int max)
{
	int padlen, strln;	/* amount to pad */
	int cnt = 0;

	if(value == 0)
	{
		value = "<NULL>";
	}

	for(strln = 0; value[strln]; ++strln);	/* strlen */
	padlen = min - strln;
	if(padlen < 0)
		padlen = 0;
	if(flags & DP_F_MINUS)
		padlen = -padlen;	/* Left Justify */

	while((padlen > 0) && (cnt < max))
	{
		dopr_outch(buffer, currlen, maxlen, ' ');
		--padlen;
		++cnt;
	}
	while(*value && (cnt < max))
	{
		dopr_outch(buffer, currlen, maxlen, *value++);
		++cnt;
	}
	while((padlen < 0) && (cnt < max))
	{
		dopr_outch(buffer, currlen, maxlen, ' ');
		++padlen;
		++cnt;
	}
}

/* Have to handle DP_F_NUM (ie 0x and 0 alternates) */

static void
fmtint(char *buffer, size_t * currlen, size_t maxlen,
       long value, int base, int min, int max, int flags)
{
	int signvalue = 0;
	unsigned long uvalue;
	char convert[20];
	int place = 0;
	int spadlen = 0;	/* amount to space pad */
	int zpadlen = 0;	/* amount to zero pad */
	int caps = 0;

	if(max < 0)
		max = 0;

	uvalue = value;

	if(!(flags & DP_F_UNSIGNED))
	{
		if(value < 0)
		{
			signvalue = '-';
			uvalue = -value;
		}
		else if(flags & DP_F_PLUS)	/* Do a sign (+/i) */
			signvalue = '+';
		else if(flags & DP_F_SPACE)
			signvalue = ' ';
	}

	if(flags & DP_F_UP)
		caps = 1;	/* Should characters be upper case? */

	do
	{
		convert[place++] =
			(caps ? "0123456789ABCDEF" : "0123456789abcdef")[uvalue % (unsigned) base];
		uvalue = (uvalue / (unsigned) base);
	}
	while(uvalue && (place < 20));
	if(place == 20)
		place--;
	convert[place] = 0;

	zpadlen = max - place;
	spadlen = min - MAX(max, place) - (signvalue ? 1 : 0);
	if(zpadlen < 0)
		zpadlen = 0;
	if(spadlen < 0)
		spadlen = 0;
	if(flags & DP_F_ZERO)
	{
		zpadlen = MAX(zpadlen, spadlen);
		spadlen = 0;
	}
	if(flags & DP_F_MINUS)
		spadlen = -spadlen;	/* Left Justifty */

#ifdef DEBUG_SNPRINTF
	dprint(1, (debugfile, "zpad: %d, spad: %d, min: %d, max: %d, place: %d\n",
		   zpadlen, spadlen, min, max, place));
#endif

	/* Spaces */
	while(spadlen > 0)
	{
		dopr_outch(buffer, currlen, maxlen, ' ');
		--spadlen;
	}

	/* Sign */
	if(signvalue)
		dopr_outch(buffer, currlen, maxlen, signvalue);

	/* Zeros */
	if(zpadlen > 0)
	{
		while(zpadlen > 0)
		{
			dopr_outch(buffer, currlen, maxlen, '0');
			--zpadlen;
		}
	}

	/* Digits */
	while(place > 0)
		dopr_outch(buffer, currlen, maxlen, convert[--place]);

	/* Left Justified spaces */
	while(spadlen < 0)
	{
		dopr_outch(buffer, currlen, maxlen, ' ');
		++spadlen;
	}
}

static long double
abs_val(long double value)
{
	long double result = value;

	if(value < 0)
		result = -value;

	return result;
}

static long double
pow10(int exp)
{
	long double result = 1;

	while(exp)
	{
		result *= 10;
		exp--;
	}

	return result;
}

static long
round(long double value)
{
	long intpart;

	intpart = value;
	value = value - intpart;
	if(value >= 0.5)
		intpart++;

	return intpart;
}

static void
fmtfp(char *buffer, size_t * currlen, size_t maxlen,
      long double fvalue, int min, int max, int flags)
{
	int signvalue = 0;
	long double ufvalue;
	char iconvert[20];
	char fconvert[20];
	int iplace = 0;
	int fplace = 0;
	int padlen = 0;		/* amount to pad */
	int zpadlen = 0;
	int caps = 0;
	long intpart;
	long fracpart;

	/* 
	 * AIX manpage says the default is 0, but Solaris says the default
	 * is 6, and sprintf on AIX defaults to 6
	 */
	if(max < 0)
		max = 6;

	ufvalue = abs_val(fvalue);

	if(fvalue < 0)
		signvalue = '-';
	else if(flags & DP_F_PLUS)	/* Do a sign (+/i) */
		signvalue = '+';
	else if(flags & DP_F_SPACE)
		signvalue = ' ';

	intpart = ufvalue;

	/* 
	 * Sorry, we only support 9 digits past the decimal because of our 
	 * conversion method
	 */
	if(max > 9)
		max = 9;

	/* We "cheat" by converting the fractional part to integer by
	 * multiplying by a factor of 10
	 */
	fracpart = round((pow10(max)) * (ufvalue - intpart));

	if(fracpart >= pow10(max))
	{
		intpart++;
		fracpart -= pow10(max);
	}

#ifdef DEBUG_SNPRINTF
	dprint(1, (debugfile, "fmtfp: %f =? %d.%d\n", fvalue, intpart, fracpart));
#endif

	/* Convert integer part */
	do
	{
		iconvert[iplace++] = (caps ? "0123456789ABCDEF" : "0123456789abcdef")[intpart % 10];
		intpart = (intpart / 10);
	}
	while(intpart && (iplace < 20));
	if(iplace == 20)
		iplace--;
	iconvert[iplace] = 0;

	/* Convert fractional part */
	do
	{
		fconvert[fplace++] =
			(caps ? "0123456789ABCDEF" : "0123456789abcdef")[fracpart % 10];
		fracpart = (fracpart / 10);
	}
	while(fracpart && (fplace < 20));
	if(fplace == 20)
		fplace--;
	fconvert[fplace] = 0;

	/* -1 for decimal point, another -1 if we are printing a sign */
	padlen = min - iplace - max - 1 - ((signvalue) ? 1 : 0);
	zpadlen = max - fplace;
	if(zpadlen < 0)
		zpadlen = 0;
	if(padlen < 0)
		padlen = 0;
	if(flags & DP_F_MINUS)
		padlen = -padlen;	/* Left Justifty */

	if((flags & DP_F_ZERO) && (padlen > 0))
	{
		if(signvalue)
		{
			dopr_outch(buffer, currlen, maxlen, signvalue);
			--padlen;
			signvalue = 0;
		}
		while(padlen > 0)
		{
			dopr_outch(buffer, currlen, maxlen, '0');
			--padlen;
		}
	}
	while(padlen > 0)
	{
		dopr_outch(buffer, currlen, maxlen, ' ');
		--padlen;
	}
	if(signvalue)
		dopr_outch(buffer, currlen, maxlen, signvalue);

	while(iplace > 0)
		dopr_outch(buffer, currlen, maxlen, iconvert[--iplace]);

	/*
	 * Decimal point.  This should probably use locale to find the correct
	 * char to print out.
	 */
	dopr_outch(buffer, currlen, maxlen, '.');

	while(fplace > 0)
		dopr_outch(buffer, currlen, maxlen, fconvert[--fplace]);

	while(zpadlen > 0)
	{
		dopr_outch(buffer, currlen, maxlen, '0');
		--zpadlen;
	}

	while(padlen < 0)
	{
		dopr_outch(buffer, currlen, maxlen, ' ');
		++padlen;
	}
}

static void
dopr_outch(char *buffer, size_t * currlen, size_t maxlen, char c)
{
	if(*currlen < maxlen)
		buffer[(*currlen)++] = c;
}
#endif /* !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF) */

#ifndef HAVE_VSNPRINTF
int
vsnprintf(char *str, size_t count, const char *fmt, va_list args)
{
	str[0] = 0;
	dopr(str, count, fmt, args);
	return (strlen(str));
}
#endif /* !HAVE_VSNPRINTF */

#ifndef HAVE_SNPRINTF
/* VARARGS3 */
#ifdef HAVE_STDARGS
int
snprintf(char *str, size_t count, const char *fmt, ...)
#else
int
snprintf(va_alist)
     va_dcl
#endif
{
#ifndef HAVE_STDARGS
	char *str;
	size_t count;
	char *fmt;
#endif
	VA_LOCAL_DECL;

	VA_START(fmt);
	VA_SHIFT(str, char *);
	VA_SHIFT(count, size_t);
	VA_SHIFT(fmt, char *);
	(void) vsnprintf(str, count, fmt, ap);
	VA_END;
	return (strlen(str));
}

#ifdef TEST_SNPRINTF
#ifndef LONG_STRING
#define LONG_STRING 1024
#endif
int
main(void)
{
	char buf1[LONG_STRING];
	char buf2[LONG_STRING];
	char *fp_fmt[] = {
		"%-1.5f",
		"%1.5f",
		"%123.9f",
		"%10.5f",
		"% 10.5f",
		"%+22.9f",
		"%+4.9f",
		"%01.3f",
		"%4f",
		"%3.1f",
		"%3.2f",
		NULL
	};
	double fp_nums[] = { -1.5, 134.21, 91340.2, 341.1234, 0203.9, 0.96, 0.996,
		0.9996, 1.996, 4.136, 0
	};
	char *int_fmt[] = {
		"%-1.5d",
		"%1.5d",
		"%123.9d",
		"%5.5d",
		"%10.5d",
		"% 10.5d",
		"%+22.33d",
		"%01.3d",
		"%4d",
		NULL
	};
	long int_nums[] = { -1, 134, 91340, 341, 0203, 0 };
	int x, y;
	int fail = 0;
	int num = 0;

	printf("Testing snprintf format codes against system sprintf...\n");

	for(x = 0; fp_fmt[x] != NULL; x++)
		for(y = 0; fp_nums[y] != 0; y++)
		{
			snprintf(buf1, sizeof(buf1), fp_fmt[x], fp_nums[y]);
			sprintf(buf2, fp_fmt[x], fp_nums[y]);
			if(strcmp(buf1, buf2))
			{
				printf("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n",	/* __SPRINTF_CHECKED__ */
				       fp_fmt[x], buf1, buf2);
				fail++;
			}
			num++;
		}

	for(x = 0; int_fmt[x] != NULL; x++)
		for(y = 0; int_nums[y] != 0; y++)
		{
			snprintf(buf1, sizeof(buf1), int_fmt[x], int_nums[y]);
			sprintf(buf2, int_fmt[x], int_nums[y]);
			if(strcmp(buf1, buf2))
			{
				printf("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n",	/* __SPRINTF_CHECKED__ */
				       int_fmt[x], buf1, buf2);
				fail++;
			}
			num++;
		}
	printf("%d tests failed out of %d.\n", fail, num);
}
#endif /* SNPRINTF_TEST */

#endif /* !HAVE_SNPRINTF */
